Coloring walnut veneer sheets



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STATES .O'FFICE i v I' 'nnwm roman. MENGEL, or xnoxvrrin E fl I I p -oo r.omncwar.nnr mean 'snanrs m, fl 5g j j p Application 1 l1edl)etober20,19 28. Seria1No. 31i !;848.

- This invention relates particularly to a it would become diflicult or impossible for method or process for coloring the sap wood the manufacturer to give the sheet surface a I of black walnut veneer sheets to make the finish. p f color of the sapwood conform to or ha'r- Another object of the invention-isto ef- 6 monize with-the color of the heart wood. feet the coloring of the sap wood part of F V It is' known that the outer part of most such a sheet without materially changing black walnut logsis composed of a. light or the color or color shade of the heart wood .whitish wood called sap wood, while the of the same sheet. In this connection it is inner portion is ofa dark or brownish gray to be noted that some of the veneer sheets- 10 color and is"calld heart'wood. When the cut from the exterior of the log are all sap log is cut int-oveneer, the veneer produced wood, While other sheets are composed infrom this whitish or sap portion has much part of sap wood and in part of heart wood... less'market value than has the veneer cut from In treating the sheets containing the light the brownish grayjor heart portion; For wood and the dark Wood, the 00101 o h 1 example, sap walnut'veneer 1/28 of an inch darkwood is not" to .be'm'aterially changed. i p 'in thickness will sell -for seven dollars per My method or process of treating the i 0 per thousand'feet; This difference in price a smallpercentagexof iron salts (FeSO or:

- manufacture of furnitureand similarw v orkmthis solut thousand feet, while the heart wood veneer "Veneer sheets is as follows: of the same thickness andcut from the same Prepare a solution of hot water, chestnut-p log will bringapproximately twenty dollars extract (or tanmc acid in anyv form) and i d t th f ct th tsthebrownish gray 'FeClg). I have obtained good results by:

heart wood is much more desirable in'the measuring thechestnut extract andwat -of r I} I on in the proportion of one 'pa-rtof Furniture manufacturerssometimes buyf'tlie"'the extract to six parts -of water,- The so-' .I

' 25 sap walnut veneer,fgl ue it onipanels or. other "lution is to be kept at-less than the boiling, 7 v

' .r .ficially; to resemble the heart wood veneer. renheit. ByeXperiment'I have learned that,

' .-coloring' to the surfaces oi the sheet; This. to soften jor dissolve orfwa-sh any objec- 1 45 sanding, removes apart of the surface of the the surface of the sheets, If the tannic acid bases, sand-'paperfit, and then color it superpoint of water, preferably aboutYIGOfFa'h- But this process is unsatisfactory because of if the solution isikept at a temperature higher the f extra labor 'invblved and the deficient than above indicated, the tannic 'acid will coloring, Thatthat method is unsatisfacbreak down and form other compounds which 7 tory and substantially impractical is to be ill pr du a black, 11 n th S rfa e of inferred-from the-factthat the'ma'nufacturers"the'veneer. t 4 f arewilling to pay such diife'ren'ce'in hases Then immerse the veneer sheets in',this Ihave'a'bove indicated. solution, and so arrange them that all, por- 35 The objectof my invention is to impart tions will be reached by the solution. The a .to the sap wood of the veneer sheet a colorsheet may be immersed whenthey al fresh ing which will closely resemble the natural from the cutting machine 01 a f y Q color of the heart woodn' been d i 1 y A ,further object is to e'fiect penetration After immersion; has continued about 9 of suchfcolorin'gvof the sap wood part of a eleven hours, the temperature-of the solu -j sheet of walnutveneer'substantially uniform tio'n having been maintained, thefvene'er is 1y throughthesheet, and not limiting the removed and 'placedinhot-or boiling water .is essential because the-manufacturer, by tionable deposits that may have formed, on

sheet'after it has been glued to the piec e'of and the'iron saltsare fresh, and no objection- I furnitureor other-base. ablyhigh temperature has been reached in Another object of the invention is to per my part of the solution,"such deposits wi'llf form the coloring without changing or dam- .bev absent and this washing step' will notbe aging-the fiber textureof thesheet, whereby necessary, Then,-whe'ther the'washing step 9 has or has not been taken, the sheets are,

preferably, rinsed. in warm or hot water.

Next, the veneer sheets areremoved and stacked upright so as to drain ofl as much of the solution as possible. The sheets are then dried in the usual manner of drying veneer sheets. I

I have -found, in practice, that the best procedure, inorder to avoid checking, buckling,

But usual into the solution byt cracking, etc. (if the sheets, is to allow the sheets to drain in an upright position ,for three or four hours. i I I Then partially dry the sheets in an ordinary mechan'ical'hot-air drier at a temperature lower than ordinarily employed in such drink-preferably, about 180 Fahrenheit;

This drying is to be continued until the moisture content'iii thesheets is about nine per cent. I' i Then press the sheets fiat in a hot plate 'drier to about a six per cent moisture content.

acid and a small quantity of iron salts are used, a brownish fray color (the color of walnut) is rocure f sap walnut veneer is immerse ina solution of iron salts and water, the iron acts on the tannin on the surface. of the veneer, thus forming a black deposit, the surface of the veneer then being very dark"while the inside remains light. The introduction of tannic acid in quantity hastens the rocess and prevents the objectionable blac deposit and gives the desired.

brownish gray color throughout-the wood. y the heart wood contains a larger proportion oftanning or tannic. acid than is contained in the sap wood. Hence when the veneer sheets contain considerablei In a solution kept at a temperature of approximately 170 Fahrenheit, .the tannlc extract remains in normal form ap roximately 100 hours. Thereafter the tannin is modified to such extent as to render the solution ineffective. But I have found that the normal or effective condition of the solution may be prolonged by acidifying it with a small quantity of acid such as sulphuric acid;

I cla1m as my invention:

1. In the art of coloring sap walnut veneer, the process which consists in immersing the veneer sheets in a solution of iron salts and tannic acid and water, in substantially the proportions stated, and Keeping the solution at a temperature of approximately 160, then removin the sheets and draining them; then partial y drying the sheets; and then hot pressing the sheets.

2. In the art of coloring sap walnut veneer, the process which consists in immersing the veneer sheets in a solution of iron salts and tannic acid and water, in substantially the proportions stated, and keeping the solution at a temperature of approximately 160, then removing the sheets and rinsing and drain ing them; then partially d" ing the sheets; and then hot pressing the s eets.

3. In the art of coloring sap walnut veneer, the herein described process which consists in exposing the :veneer sheets to the action of a heated solution of water,tannicacid and iron salts, then draining, then partially dry- 7 ing; and then hot pressing-the sheets. I

4. In the art of 0010' 'ng sap walnut veneer, the process which co sists m exposing the veneer sheets to the action of a heated solution of water and iron salts then rinsing, then plzlirtially drying; then hot pressing the s eets.

In testimony whereof'I have signed my name, this sixteenth da of October, in the year one thousand nine eight.

. EDWIN POTTER MENGEL.

undrjed and twentyarts of heart wood the tannin delivered sap wood will be in suflicient quantity to render extraneous addition. of, tanning or heart w "tannic acid unnecessary.

When a veneer sheet is com d in part e heart wood and the of sap wood and in partof heart wood. and is subjected to the above method or procwood and seem to have little effect on the heartwood, so that it is generally impossible or dlflicult to tell where t -ess, the iron and tannic acid color the sap e sap wood and the heart wood-meet. But even-when the difieronce in coloring is suflicie ntto'allow seeing the meetin line of thesap wood and the that difierence in. coloring is so'slighta's to be unobjeetionable in the trade. v 

